[HackerRank] Pairs (PYTHON)

문제

Given an array of integers and a target value, determine the number of pairs of array elements that have a difference equal to the target value.링크

Example

There are three values that differ by : , , and . Return .

Function Description

Complete the pairs function below.

pairs has the following parameter(s):

• int k: an integer, the target difference
• int arr[n]: an array of integers

입력

• The first line contains two space-separated integers  and , the size of  and the target value.
  The second line contains  space-separated integers of the array .

반환값

• int: the number of pairs that satisfy the criterion

제한

• 2 <= n <= 105
• 0 < k < 109
• 0 < arr[i] < 231 - 1
• each integer arr[i] will be unique.

기록이유

• 부르트 포스로 풀이하였는데 완벽한 풀이방법이 아니라고 나왔다.

def pairs(k, arr):
    # Write your code here
    cnt = 0
    for i in range(0,len(arr)-1):
        for j in range(i+1,len(arr)):
            if abs(arr[i]-arr[j]) == k:
                cnt += 1
    return cnt

찾아보니까 해시, 이분탐색을 이용하여 풀이하였다.링크